反应详情

3-Ethoxycarbonylpropyltriphenylphosphonium bromide (73.3.g, 160 mmol) was added to a solution of potassium tert-butoxide (18.5 g, 160 mmol) in tetrahydrofuran (1000 ml) and stirred for 3 hours, and then isobutyrophenone (20.0 g, 135 mmol) was added thereto and stirred for 3 days. After water (200 ml) was added thereto and stirred for 30 minutes, the reaction mixture was added to an aqueous sodium chloride solution and extracted twice with ethyl acetate. The extract solution was washed with a saturated aqueous sodium chloride solution and dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure and the resulting residue was treated by a silica gel column chromatography (eluent: ethyl acetate/n-hexane=1/20) to obtain crude ethyl 5-phenyl-5-(2-propyl)-4-pentenoate (24.6 g; containing starting isobutyrophenone). This crude product was treated with sodium tetrahydroborate (2.83 g) in ethanol and then purified by a silica gel column chromatography (eluent: ethyl acetate/n-hexane=1/40) to obtain 10.0 g of ethyl 5-phenyl-5-(2-propyl)-4-pentenoate.

1. stirringstirred for 3 days
2. stirringstirred for 30 minutes
3. extractionextracted twice with ethyl acetate
4. washThe extract solution was washed with a saturated aqueous sodium chloride solution
5. dry with materialdried over anhydrous magnesium sulfate
6. distillationThe solvent was distilled off under reduced pressure
7. additionthe resulting residue was treated by a silica gel column chromatography (eluent: ethyl acetate/n-hexane=1/20)
8. customto obtain crude ethyl 5-phenyl-5-(2-propyl)-4-pentenoate (24.6 g; containing starting isobutyrophenone)
9. custompurified by a silica gel column chromatography (eluent: ethyl acetate/n-hexane=1/40)